JP-A-2017-65021 discloses an example of a conventional thermal printhead that includes: a main substrate provided with a wiring layer and a resistor layer; and an auxiliary substrate equipped with a driver IC. The resistor layer includes multiple heating portions aligned in a primary scanning direction.
In the printing performed by the thermal printhead, the heat generation portion of the resistor layer generates heat through electric conduction. This heat is transmitted, whereby the printing paper is colored and printing is performed.